1. Field of the Invention
The present invention relates to fluid sample collection. In particular, the invention relates to a system for collecting oral fluid samples.
2. Description of Related Art
Small quantities of materials for analysis are frequently required from subjects undergoing testing for a multitude of conditions, diseases, or the presence of pharmacologically relevant molecules that are either naturally produced or introduced into the body. For example, oral fluids may be required and used as the analytical matrix. One approach to oral fluid sample collection is to place an absorbent material in the oral cavity so that a quantity may be absorbed and subsequently transferred to a container along the with absorbent material.
Another common technique for sample collection is to have a subject expectorate into a container. Such containers may have an attachment to aid in sample collection and serve as a source for additional fluid to be mixed with the sample being obtained. The additional fluid may serve to wash the sample into the container and/or stabilize the sample.
For oral fluid samples that are collected without the use of absorbents or the addition of other fluid, the efficiency of sample collection is dependent upon the geometry of the collection device, and it is desirable that the device used for collection provide a free-flowing path to the sample container.
It is desirable that the receiver for the expectorated sample be large enough that any spray or splatter is contained and channeled into the collection tube. It is also desirable that the volume and weight of the sample container be minimized to reduce the cost of transportation and ease of handling. It is preferable that the sample container falls within the specifications of standard laboratory ware for sample handling. A sample collection device that can use an effectively large sample collection adapter during the collection process, which is then discarded once the sample container is sealed, is also preferred.
A subject providing an oral fluid sample may be less than comfortable with the act of spitting into a tube, and it is desirable that a collection device be easy to use and minimize discomfort on the part of the subject. In some cases the subjects discomfort can be mitigated with the use of a shielding apparatus that offers some privacy from the view of people other than the subject.
Some analytes may have an affinity for a collection swab or pad material due to the general nature of the compound and the material's physical properties. In some cases, this affinity will reduce the accuracy of subsequent sample analysis.
The volume of oral fluid that is absorbed by collection pads or swabs is highly variable due to many factors including collection time and oral fluid viscosity and constitution. Collection devices that place a saturated adsorbent pad or swab into a fixed volume admixture have reduced analysis accuracy due to the imprecision of the sample volume.
In cases where an adsorbent pad is used, there is additional processing required to separate the sample from the pad prior to analysis. This process can include vigorous mixing, vortexing, centrifugation or other more manual methods to retrieve the sample. These processing steps are inefficient and costly, making this type of collection undesirable.
Generally, automated or robotic liquid handling instruments demonstrate improved performance with samples that do not contain significant solids or semi-solids due to precise volume sampling that must be performed. Thus it is preferred that samples do not contain significant solids.
A sample container that is directly compatible with automated robotic sample handling and processing is desirable. A sample that can be placed directly into automatic processing line is preferred. It is also preferable that the collected sample container be adapted for automated handling as received from the collection, or with minor handling such as cap removal.
Thus, a need exists for an efficient system for collecting oral fluid samples without absorbents or admixtures of significant volume. There is also a need for a sample collection system that is easy to use.